Drawing board



N. M. SCHRUBEN DRAWING BOARD oct. 12, 1926. 1,602,942

P iled Jan. 27, 1922 Il /f k, D ElI l 11 L UL V76. f m 15A/@221f1f if f? 9 10. 1019,? j]

1&3, EGW/1.254% www Patented Oct. 12, 1926.

UNITED STATES NICHOLAS M. SCHRUBEN, 0F CHICAGO, ILLINOIS.

DRAWING BOARD.

Application filed January 27, 1922. Serial No. 532,231.

This invention relates to drawing-boards, and relates more particularly to means for clamping the paper in place. The main objects of the invention are to provide clamping means of improved construction; to

provide. such means which may be quickly tion showing the manner of inserting the locking bar.

Fig. 6 shows the paper locked in position.

In the construction shown the drawingboard 1 is provided with parallel spaced grooves 3 in which are fitted locking bars 2. Lifting means 4 are provided adjacent to one edge of the board, opposite the corresponding ends of said bars respectively.

Each groove 3 is about half as deep as it is wide, and extends preferably to a depth of about two-thirds of the thickness of the board. The grooves may be provided at the end remote from the lifting mechanism 4 with an over-hanging inclined shoul-l der 5 to receive the correspondingly formed beveled end G of the bar 2. The opposite end of the bar may be also beveled, on the under side, to bear against the correspondingly formed end S of groove 8.

The inner edge of each bar 2 is beveled at 9 and has a resilient face member 10. The bevel 9 is downwardly inclined away from the center of the board so as to be convergent with the oppositely erpendicular side 11 toward the bottom of t e strip. The inner side of each groove 3 is correspondingly beveled. The strip 10 is preferably ir. the form of rubber or a resilient composition and will effectually grip the paper when the bars are pressed into place as will be explained; but the chief function of the rubber stri n is to provide a resiliency 1n width. ai: tbe bar so that the bar taunt be forced into the slot, and, when the bar is in the slot, the expanding tendency of the rubber will exert a substantial lateral 'pressure on the walls ofthe groove to` hold the bar in place.

The bar lifting mechanism 4 comprises a lever 12 positioned in the slot-like aperture 13 which communicates with the adjacent end of groove 3, and a push button or plunger 14 disposed in the hole 15 which extends from thev upper face of the board part way through, or to about the depth 0f groove 3. Said lever is mounted on a fixed pivot 16, the ends of which are fixed in the walls of slot 13, preferably somewhat nearer the bar 3 than the button 14 so as to provide effective lifting leverage in case the bar 3 sticks when it has been forced tightly into place. The outer end of said lever is pivoted at 17 to the arms of the bifurcated lower end of button 14. The lever 12 is provided with a longitudinal slot 17 to accommodate the pivot 17. The aperture 13 is provided with a closure strip 18 which may be secured in place with glue after the lever is in place, or the cover 18 may be omitted.

The operation is as follows: The bars 3 are both removed and then the paper havig been slipped into place the bars are successively pressed downward to stretch the paper and draw it tightly into place where it is held by the pressure exerted by the rubber strips. lVhenever it is desired to'remove the paper the buttons 14 are depressed thereby tilting levers 12 and throw ing the adjacent ends of the bars upward and thereby loosening same so that they may be readily removed.

Although but one embodiment of this invention is herein shown and described it to be understood that no attempt has been made to show all practical embodiments of the invention, and that numerous details of the constructions shown may be altered or omitted without departing from the spirit of this invention as defined by the following claims.

I claim 1. In a device of the class described, a .board having achannel in the surface thereof, said channel having downwardly converging sides, and a locking 'strip conferming te the cross se'ctitnttl csrfiguraten of the channel for gripping and holding the edge of a sheet of paper inserted in the slot.

2. In a device of the class described, a,

5 yoard having spaced channels in the surface thereof, said channeie lmfingdownwardly converging Sides and having an undercut surface at one end, locking strips con-forming to the cross sectional conliguration of the channels und having @projection at one end for engaging beneath saidI under cut Surfaces.

Signed at Chicago this 21st day of Janna'ry, 1922.

NICHOLAS M. SCHRUBEN. 

